Method of insert molding a connection for catheter with varying diameters

Abstract

The present invention provides in some embodiments, a method for insert molding a coupling between catheter segments with different diameters and/or a catheter having different diameters. Generally, the method can include the steps of providing first and second tubes having larger and smaller diameters, respectively and positioning the first and second tubes onto a core pin assembly having an outer surface at one section which forms a contoured inner profile for a joint section to join the first and second tubes. Additionally, the method can include injection molding the joint section to join the first and second tubes, to form the catheter tube with the contoured inner profile at the joint section.

1 . A method of forming a medical catheter tube having sections of different diameter, comprising:
 providing first and second tubes having larger and smaller diameters, respectively;   positioning the first and second tubes onto a core pin assembly having an outer surface at one section which forms a contoured inner profile for a joint section to join the first and second tubes;   injection molding the joint section to join the first and second tubes, to form the catheter tube with the contoured inner profile at the joint section.   
     
     
         2 . The method of  claim 1 , wherein the injection molding of the joint section comprises a plurality of injection molding steps to form a plurality of layers of the joint section. 
     
     
         3 . The method of  claim 1 , flowing molten material over portions of the first and second tubes to form part of the joint section. 
     
     
         4 . A method of forming a medical catheter tube having sections of different diameter coupled at a joint section, comprising:
 providing a first length of tubing having a first, larger diameter;   providing a second length of tubing having a second, smaller diameter;   providing a set of one or more core pins arranged to provide a pre-determined inner surface profile of the catheter tube at the joint section;   positioning the first length of tubing over the set of core pins, to form a first sub-assembly;   placing the first sub-assembly into a clamshell fixture which holds the first length of tubing fixed to the set of core pins and leaves a first end portion of the set of core pins exposed, to form a second sub-assembly;   placing the second sub-assembly into a mold base;   positioning the second length of tubing over the first end portion of the set of core pins, leaving a section of the set of core pins exposed;   placing a cover mold portion over the mold base to form an inner space around the exposed section of the set of core pins; and   injection molding the joint section of the catheter tube by injecting a material into the inner space, said joint section coupling the first and second lengths of tubing and providing the pre-determined inner surface profile of the catheter tube at the joint section.   
     
     
         5 . The method of  claim 4 , further comprising:
 detaching the cover mold portion from the mold base and removing a third sub-assembly which includes the finished catheter tube, clamshell fixture and set of core pins;   placing the third sub-assembly into a catheter removal fixture to hold the third sub-assembly;   removing the set of core pins from the third sub-assembly; and   opening the clamshell fixture to remove the finished catheter tube.   
     
     
         6 . The method of  claim 4 , wherein the injection molding of the joint section of the catheter tube comprises a plurality of injection molding steps to form a plurality of layers of the joint section. 
     
     
         7 . The method of any one of  claim 4 , further comprising increasing an amount of core pins in the set of core pins. 
     
     
         8 . The method of any one of  claim 4 , further comprising interlocking a core pin with at least one other core pin. 
     
     
         9 . A catheter comprising:
 a first section having a first diameter,   a second section having a second diameter greater than the first diameter; and   a joint section connecting the first section and the second sections, the joint section having a tapered portion tapering the inner diameter of the molded section down from the first diameter to the second diameter and the joint section is molded to the first section and the second section.   
     
     
         10 . The catheter of  claim 9 , wherein the first and second sections extend into the joint section. 
     
     
         11 . The catheter of  claim 9 , wherein the catheter was fabricated by:
 providing first and second tubes having larger and smaller diameters, respectively;   positioning the first and second tubes onto a core pin assembly having an outer surface at one section which forms a contoured inner profile for a joint section to join the first and second tubes;   injection molding the joint section to join the first and second tubes, to form the catheter tube with the contoured inner profile at the joint section.   
     
     
         12 . The catheter of  claim 9 , wherein the catheter was fabricated by:
 providing a first length of tubing having a first, larger diameter;   providing a second length of tubing having a second, smaller diameter;   providing a set of one or more core pins arranged to provide a pre-determined inner surface profile of the catheter tube at the joint section;   positioning the first length of tubing over the set of core pins, to form a first sub-assembly;   placing the first sub-assembly into a clamshell fixture which holds the first length of tubing fixed to the set of core pins and leaves a first end portion of the set of core pins exposed, to form a second sub-assembly;   placing the second sub-assembly into a mold base;   positioning the second length of tubing over the first end portion of the set of core pins, leaving a section of the set of core pins exposed;   placing a cover mold portion over the mold base to form an inner space around the exposed section of the set of core pins; and   injection molding the joint section of the catheter tube by injecting a material into the inner space, said joint section coupling the first and second lengths of tubing and providing the pre-determined inner surface profile of the catheter tube at the joint section.   
     
     
         13 . The catheter of  claim 9 , wherein the first and second sections were cut to a desired length prior to being attached to the joint section. 
     
     
         14 . The catheter of  claim 9 , wherein when the joint section is molded molten material flows to cover at least part of an outer diameter of the first section and an outer diameter of the second section. 
     
     
         15 . The catheter of  claim 9 , wherein the joint section is unitized to the first and second sections.